code: def test_bbox():
      img = np.zeros((10, 10), np.uint16)
  
      a0, b0, a1, b1 = bbox(img)
      assert a0 == b0
      assert a1 == b1
  
      img[4, 2] = 1
      a0, b0, a1, b1 = bbox(img)
      assert a0 == 4
      assert b0 == 5
      assert a1 == 2
      assert b1 == 3
  
      img[6, 8] = 1
      a0, b0, a1, b1 = bbox(img)
      assert a0 == 4
      assert b0 == 7
      assert a1 == 2
      assert b1 == 9
  
      img[7, 7] = 1
      a0, b0, a1, b1 = bbox(img)
      assert a0 == 4
      assert b0 == 8
      assert a1 == 2
      assert b1 == 9
  
      c0, d0, c1, d1 = bbox(img, 0)
      assert c0 == a0
      assert b0 == d0
      assert c1 == a1
      assert b1 == d1
  
      c0, d0, c1, d1 = bbox(img, 1)
      assert c0 != a0
      assert b0 != d0
      assert c1 != a1
      assert b1 != d1
  
file_path: mahotas/mahotas/tests/test_bbox.py
imports: import numpy
  import mahotas
  import mahotas
  from mahotas import bbox
label_desc: Use image node_id 5 for calling a global function with example usage: test_bbox() without return types